Recent Innovations in Non-dairy Prebiotics and Probiotics: Physiological Potential, Applications, and Characterization

Non-dairy sources of prebiotics and probiotics impart various physiological functions in the prevention and management of chronic metabolic disorders, therefore nutraceuticals emerged as a potential industry. Extraction of prebiotics from non-dairy sources is economical and easily implemented. Waste products during food processing, including fruit peels and fruit skins, can be utilized as a promising source of prebiotics and considered "Generally Recognized As Safe" for human consumption. Prebiotics from non-dairy sources have a significant impact on gut microbiota and reduce the population of pathogenic bacteria. Similarly, next-generation probiotics could also be isolated from non-dairy sources. These sources have considerable potential and can give novel strains of probiotics, which can be the replacement for dairy sources. Such strains isolated from non-dairy sources have good probiotic properties and can be used as therapeutic. This review will elaborate on the potential non-dairy sources of prebiotics and probiotics, their characterization, and significant physiological potential.

Debridement, antibiotics, and implant retention in non-oncological femoral megaprosthesis infections: minimum 5 year follow-up

Purpose

Megaprostheses are increasingly utilised outside of the oncological setting, and remain at significant risk of periprosthetic joint infection (PJI). Debridement, antibiotic, and implant retention (DAIR) is an established treatment for PJI, however its use in non-oncological patients with femoral megaprostheses has not been widely reported. There are significant differences in patient physiology, treatment goals, and associated risks between these patient cohorts.

Methods

We identified 14 patients who underwent DAIR for a PJI of their femoral megaprostheses, between 2000 and 2014, whom had their index procedure secondary to non-oncological indications. Patients were managed as part of a multidisciplinary team, with our standardised surgical technique including exchange of all mobile parts, and subsequent antibiotic therapy for a minimum of 3 months. Patients were followed up for a minimum of 5 years.

Results

Patients included six proximal femoral replacements, five distal femoral replacements, and three total femoral replacements. No patients were lost to follow-up. There were six males and eight females, with a mean age of 67.2 years, and mean ASA of 2.3.

Nine patients (64.3%) successfully cleared their infection following DAIR at a minimum of 5 year follow-up. Five patients (35.7%) required further revision surgery, with four patients cleared of infection. No patients who underwent DAIR alone suffered complications as a result of the procedure.

Conclusions

The use of DAIR in these complex patients can lead to successful outcomes, but the risk of further revision remains high. The success rate (64.3%) remains on par with other studies evaluating DAIR in megaprostheses and in primary arthroplasty. This study indicates judicious use of DAIR can be an appropriate part of the treatment algorithm.

Level of evidence

II

Bifunctional Composites for Biofilms Modulation on Cervical Restorations

Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM-20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum by 3 to 5-log (P < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera Veillonella, Fusobacterium, Streptococcus, Eikenella, and Leptotrichia, while Fusobacterium and Veillonella dominated the 5% DMAHDM-20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations' life span.

Comparing Antenatal and Delivery Care Services in Public and Private Health Facilities: Evidence from 2018 Nigeria Demographic and Health Survey

BACKGROUND

There have been calls for privatisation of public health facilities to improve quality of care received. The study compared antenatal and delivery services received in public and private health facilities in Nigeria.

METHODS

The study was based on 2018 Nigeria Demographic and Health Survey data collected from women aged 15-49 years, concerning their pregnancy and delivery. Data on those that attended antenatal clinic (ANC) in public or private facilities and had live births in the preceding five years was analysed. Simple logistic regression was used to test for association between type of facility for ANC and delivery and the care received.

RESULTS

A total of 15,811 women attended ANC in public (12,921, 81.7%) and private (2,890, 18.3%) facilities, and 12,399 delivered in public (8,583, 69.2%) and private (3,817, 30.8%) facilities. Type of facility attended was associated with number of ANC visits (OR=3.89; p<0.001), blood sample taken (OR=1.16; p=0.029), iron supplementation (OR=0.49; p<0.001), deworming (OR=0.74; p<0.001), receiving all the components of ANC service (OR=0.79; p<0.001), and skilled birth attendance (OR=3.81; p<0.001). However, it was not associated with blood pressure measurement (OR=1.07; p=0.459), urine sample taken (OR=1.05; p=0.486), postnatal check (OR=0.94; p=0.171) and timing of postnatal check (OR=0.73; p=0.185).

CONCLUSION

While private facilities had more ANC visits and skilled birth attendance, overall provision of ANC services was better in the public facilities. Therefore, antenatal and delivery services were not necessarily better in private facilities. Beyond availability, further studies are needed to compare the quality of antenatal and delivery services in public and private facilities.

Characterization and classification of soils of Wadi Qena, Eastern Desert, Egypt

An investigation was carried out to characterize and classify some soils from Wadi Qena, Eastern Desert, Egypt. Twelve representative profiles were chosen based on DEM extracted from the Landsat 8 ETM+ satellite image. The soils were moderately deep to deep in depth, well drained, slightly to strongly alkaline in soil reaction (pH 7.6 – 8.4), slight to moderate saline (EC 3.3- 15.4 dS.m-1). The soils were low in organic matter (0.09 – 0.65%), low in CEC (1.5–8.1 cmol (p+).kg-1) and calcium carbonates ranged from (1.2 – 18.2%). The results revealed that the soils were low in available N (1–21 kg.ha-1), low in available P (1.0 – 9 kg.ha-1), and low to high in available K (105 – 762 kg.ha-1). Further, the soils were low in available micronutrients. Soil classification of the investigated area is done according to the field survey, morphological description and soil analyses. Two soil orders, viz Entisols and Aridisols were recognized in the study area. The soils were keyed out as Typic Torripsamments and Typic Haplocalcids at subgroup level. The obtained results can be used by decision makers to focus on prospective agricultural areas and to achieve land reclamation and better agricultural production.

Knowledge and perception of episiotomy among women attending antenatal clinic in a secondary health facility in North-West Nigeria

Background

Episiotomy is a common surgical procedure experienced by women worldwide to ease labor and improve its outcome. However, it could influence the use of delivery services because of its associated complications. The study assessed knowledge and perception of episiotomy among antenatal clinic (ANC) attendees.

Methods

It was a cross-sectional study conducted among 218 women attending ANC in a secondary health facility in Northwestern Nigeria. Data were collected using a structured, interviewer-administered questionnaire and were analyzed using IBM SPSS Statistics 20.

Results

The mean age of women attending ANC was 24.2 ± 6.6 years, and 31 (14.2%) of them had had an episiotomy in the past. A majority of them were aware of episiotomy (87.6%) and had good knowledge (83.5%) and good perception (77.5%) of it. In addition, a majority (89.0%) were willing to deliver at the facility even if episiotomy would be given during labor. Knowledge of episiotomy showed statistically significant association with only a history of previous delivery while perception did not show statistically significant association with any of the independent variables.

Conclusions

Awareness and knowledge of episiotomy among women attending ANC were high and perception of it was generally good. The major factor associated with the knowledge of episiotomy was a history of previous delivery. Effort should be channeled toward improving awareness and knowledge on episiotomy among intending mothers, and health workers should always ensure that women are adequately informed and counseled before an episiotomy is given to them.

Blood Hematological and Biochemical Constituents, Antioxidant Enzymes, Immunity and Lymphoid Organs of Broiler Chicks Supplemented with Propolis, Bee Pollen and Mannan Oligosaccharides Continuously or Intermittently

This study investigate the effect of bee pollen (BP) and/or propolis (Pro) as an alternative to Mannan oligosaccharides (Bio-MOS, a hydrolyzed yeast with natural and artificial flavors Alltech Inc) when given continuously or intermittently on antioxidant enzymes, immunity, weight and morphology of lymphoid organs of broilers. Thus, 324 unsexed one-day-old Arbor Acres broilers were randomly distributed into nine treatment groups, each replicated 6 times of 6 birds per replicate. The chicks were kept in wire cages and fed the same basal diet and were submitted to the following treatments: control without supplementation (control) or supplemented with BP at 300 mg, Pro at 300 mg, BP+Pro at 300 mg each and Bio-MOS at 0.5 g/kg diet. Each supplemented group was subdivided into two subgroups in which the additives were supplied continuously or intermittently. In the continuously supplemented groups, supplementations were given from one till 36 days of age, and in the intermittently supplemented groups, the administration was only three days before, on the day of and day after vaccination. The BP and Pro supplied continuously or intermittently was equally potent for improving immunity, antioxidant enzymes similar to Bio-MOS. All supplements supplied either continuously or intermittently resulted a significantly higher thymus (P < .04) and bursa weights (P < .001) than the control group. Combining BP with Pro resulted in a further increase in thymus weights and small follicle diameter compared to the control group. In addition, thymus percentage in the group received BP+Pro showed a further increase compared to the control and Pro supplemented intermittently. Bio-MOS, when supplied continuously or intermittently, resulted in the greatest response in splenic lymphoblasts. Supplementation with either BP or Pro intermittently, is adequate to promote health and immune response of broiler chicks, with 40% saving of supplementation costs.

Two-stage revision for the culture-negative infected total hip arthroplasty : A comparative study

Aims

Periprosthetic joint infection (PJI) remains a challenging complication following total hip arthroplasty (THA). It is associated with high levels of morbidity, mortality and expense. Guidelines and protocols exist for the management of culture-positive patients. Managing culture-negative patients with a PJI poses a greater challenge to surgeons and the wider multidisciplinary team as clear guidance is lacking.

Patients and Methods

We aimed to compare the outcomes of treatment for 50 consecutive culture-negative and 50 consecutive culture-positive patients who underwent two-stage revision THA for chronic infection with a minimum follow-up of five years.

Results

There was no significant difference in the outcomes between the two groups of patients, with a similar rate of re-infection of 6%, five years post-operatively. Culture-negative PJIs were associated with older age, smoking, referral from elsewhere and pre-operative antibiotic treatment. The samples in the culture-negative patients were negative before the first stage (aspiration), during the first-stage (implant removal) and second-stage procedures (re-implantation).

Conclusion

Adherence to strict protocols for selecting and treating culture-negative patients with a PJI using the same two-stage revision approach that we employ for complex culture-positive PJIs is important in order to achieve control of the infection in this difficult group of patients.

Cite this article: Bone Joint J 2018;(1 Supple A)100-B:3–8.

Financial analysis of revision knee surgery based on NHS tariffs and hospital costs: does it pay to provide a revision service?

Revision total knee arthroplasty (TKA) is a complex procedure which carries both a greater risk for patients and greater cost for the treating hospital than does a primary TKA. As well as the increased cost of peri-operative investigations, blood transfusions, surgical instrumentation, implants and operating time, there is a well-documented increased length of stay which accounts for most of the actual costs associated with surgery. We compared revision surgery for infection with revision for other causes (pain, instability, aseptic loosening and fracture). Complete clinical, demographic and economic data were obtained for 168 consecutive revision TKAs performed at a tertiary referral centre between 2005 and 2012. Revision surgery for infection was associated with a mean length of stay more than double that of aseptic cases (21.5 vs 9.5 days, p < 0.0001). The mean cost of a revision for infection was more than three times that of an aseptic revision (£30 011 (sd 4514) vs £9655 (sd 599.7), p < 0.0001). Current NHS tariffs do not fully reimburse the increased costs of providing a revision knee surgery service. Moreover, especially as greater costs are incurred for infected cases. These losses may adversely affect the provision of revision surgery in the NHS.

Enhanced recovery in total hip replacement: a clinical review

The outcome after total hip replacement has improved with the development of surgical techniques, better pain management and the introduction of enhanced recovery pathways. These pathways require a multidisciplinary team to manage pre-operative education, multimodal pain control and accelerated rehabilitation. The current economic climate and restricted budgets favour brief hospitalisation while minimising costs. This has put considerable pressure on hospitals to combine excellent results, early functional recovery and shorter admissions. In this review we present an evidence-based summary of some common interventions and methods, including pre-operative patient education, pre-emptive analgesia, local infiltration analgesia, pre-operative nutrition, the use of pulsed electromagnetic fields, peri-operative rehabilitation, wound dressings, different surgical techniques, minimally invasive surgery and fast-track joint replacement units.

An evidence-based review of enhanced recovery interventions in knee replacement surgery

INTRODUCTION

Total knee replacement (TKR) is a very common surgical procedure. Improved pain management techniques, surgical practices and the introduction of novel interventions have enhanced the patient's postoperative experience after TKR. Safe, efficient pathways are needed to address the increasing need for knee arthroplasty in the UK. Enhanced recovery programmes can help to reduce hospital stays following knee replacements while maintaining patient safety and satisfaction. This review outlines common evidence-based pre, intra and postoperative interventions in use in enhanced recovery protocols following TKR.

METHODS

A thorough literature search of the electronic healthcare databases (MEDLINE(®), Embase™ and the Cochrane Library) was conducted to identify articles and studies concerned with enhanced recovery and fast track pathways for TKR.

RESULTS

A literature review revealed several non-operative and operative interventions that are effective in enhanced recovery following TKR including preoperative patient education, pre-emptive and local infiltration analgesia, preoperative nutrition, neuromuscular electrical stimulation, pulsed electromagnetic fields, perioperative rehabilitation, modern wound dressings, different standard surgical techniques, minimally invasive surgery and computer assisted surgery.

CONCLUSIONS

Enhanced recovery programmes require a multidisciplinary team of dedicated professionals, principally involving preoperative education, multimodal pain control and accelerated rehabilitation; this will be boosted if combined with minimally invasive surgery. The current economic climate and restricted healthcare budget further necessitate brief hospitalisation while minimising costs. These non-operative interventions are the way forward to achieve such requirements.

Voltammetric and spectroscopic studies on binding of antitumor Morin, Morin-Cu complex and Morin-beta-cyclodextrin with DNA

A systematic comparative study of the binding of antitumor Morin and its complexes with DNA has been investigated in the Britton-Robison (BR) buffer solutions using voltammetric and spectroscopic methods. The results show that Morin molecule, acting as an intercalator, is inserted into the cavity of the beta-cyclodextrin (beta-CD) as well as into the base stacking domain of the DNA double helix. The interaction of Morin-Cu complex or the inclusion complex of Morin-beta-CD with ds-DNA causes hypochromism in the absorption spectra, along with pronounced changes in the electrochemical behavior of the Morin complexes. An isobestic point and a new spectrum band appeared indicating the formation of the new system of Morin-Cu-DNA at lambda(m)=391 nm and Morin-beta-CD-DNA at lambda(m)=375 nm. The intercalation of Morin-Cu and Morin-beta-CD complexes with DNA produces an electrochemically inactive supramolecular complex. The binding constants were calculated from the increase of the solubility, the strong hypochromism, and the decrease in peak current of Morin and its complexes upon the addition of the host molecules. Calculation of the thermodynamic parameters of the interaction of the inclusion complex of Morin-beta-CD with DNA, including Gibbs free energy change, Helmholz free energy and entropy change shows that the complexation is a spontaneous process of association.

Two-color multiplex assay for the identification of orthopox viruses with real-time LUX- PCR

The LUX [Light Upon eXtension] is a real-time detection system that can be used for the detection and quantification of pathogens nucleic acids. In this study we used a universal LUX approach, a variation of the LUX detection system, for identifying Orthopoxvirus nucleic acids in real time. This approach enables the design of sequence-specific primer sets in high identity genome sequences. The assay described here is designed to allow simultaneous detection of Variola and other orthopox viruses in a multiplex format, with a limit of detection in the range of 50--100 copies of the Orthopoxvirus genome. Regression analysis showed that the assay was linear over seven orders of magnitude, with 0.97 correlation coefficient. The sensitivity and specificity of the assay, as determined from a panel of 100 samples that contained nucleic acids from a variety of bacteria and viral species, were rated at 98%. Thus, the assay offers a sensitive and specific tool for simultaneous identification and quantification of Variola and other orthopox viruses, and the approach allows more flexible sequence-specific primers design for pox viruses as well as other microbial pathogens.

Comparison of the voltammetric studies at mercury and glassy carbon electrodes for the interaction of lumichrome with DNA and analytical applications

The determination of the interaction between lumichrome (LC), one of the products of decomposition of the biologically important flavins, and calf thymus double-stranded DNA was performed by using cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV) in connection with a hanging mercury drop electrode (HMDE) or glassy carbon electrode (GCE). The nature of the process taking place at both electrode surfaces was clarified. It was found that the addition of DNA to a buffered LC solution results in the decrease of redox peak currents with changes in the peak potentials at both electrodes. We assume that LC interacting with DNA produces an electrochemically inactive supramolecular complex via intercalation. There was a difference between the electrochemical parameters determined at the HMDE and those at the GCE. The binding constants ( K) of the LC-DNA complex at HMDE and GCE were determined through the changes of peak currents and their values at the 10(5) level and 10(4) level with each nucleotide residue of DNA binding one LC molecule, respectively. Furthermore, the calibration graph for the determination of DNA was obtained by the decrease in the DPSV peak current of LC in the presence of DNA. Different variables, such as the concentration of LC, the accumulation time and solution conditions, were studied and optimised to maximize the sensitivity; in addition, the detection limit and the reproducibility were determined.

The antimicrobial nalidixic acid as a probe for molecular recognition of α- and β-cyclodextrins

The inclusion of the antibacterial drug nalidixic acid (NAL) in α- and β-cyclodextrin (CD) cavities was studied using UV–vis absorption and voltammetric methods. It was corroborated that the UV absorption bands of NAL are intensified in the presence of α- and β-CDs. A pronounced decrease in the peak currents of NAL was also noticed upon the addition of α- and β-CDs. From the changes in the peak currents, it was concluded that NAL forms 1:1 inclusion complexes with the various hosts, which is also revealed in the phase solubility profile of the NAL–β-CD system, as a representative example. From voltammetric data, the logarithm of the binding constants were calculated to be 2.60 and 3.20 for α- and β-CDs, respectively. The magnitude of the formation constants, as well as the Gibbs free energies for NAL with α- and β-CDs, shows that NAL is bound more strongly to β-CD, with a more apolar cavity, than to α-CD. These observations suggest that hydrophobic interaction is the most important recognition element in the binding process. All orientations of entering NAL into the cavity have been considered herein, with the purpose of characterizing the inclusion complex of NAL with CD. Combining the experimental results and molecular modeling and energy calculations on the inclusion complexes yielded a more detailed picture of the solution structure of the complex formed between NAL and either α-CD or β-CD. It was inferred that the inclusion process can occur through the 2-methylpyridine side. An additional hydrogen bond was also found to be formed between the carboxyl group of NAL, which remains outside the β-CD cavity, and the secondary hydroxyl group of β-CD. This hydrogen bond should, therefore, be operating as an important second recognition element in the NAL–β-CD system. Key words: cyclodextrins, host–guest association, inclusion complexes, nalidixic acid, solubility, voltammetry.

Voltammetric studies of the interaction of lumazine with cyclodextrins and DNA

The interaction of lumazine, an antibacterial drug, with alpha-, beta-cyclodextrins and DNA in aqueous solution was studied by differential pulse stripping voltammetry and cyclic voltammetry as well as UV-vis spectroscopy. The electrochemical and absorption spectral data indicated a 1:1 complex formation of lumazine with alpha-, beta-cyclodextrins and DNA. The nature of the process, taking place at the hanging mercury drop electrode, was clarified. It was found that the complexation of lumazine molecules enhances the stacking interactions which might facilitate the formation of a perpendicularly stacked layer of lumazine-alpha-cyclodextrin complex on the electrode surface. Based on the variations in the current or absorbance, the formation constants and consequently, the Gibbs energy of these complexes were determined. The small size cavity of alpha-cyclodextrin was found to have a greater affinity for lumazine than the beta-cyclodextrin. Moreover, the interactions of lumazine-alpha-cyclodextrin or lumazine-beta-cyclodextrin inclusion complex with DNA have been investigated by means of voltammetry. The results suggest that lumazine displayed high affinity for DNA and the inclusion complex decomposed when it binds to DNA.

Binding of anti-inflammatory drug indomethacin with cyclodextrin and DNA: solubility, spectroscopic, and voltammetric studies

The interaction of the anti-inflammatory drug indomethacin (IMC) with α-, β-cyclodextrins (CDs) and calf thymus deoxyribonucleic acid (ct-DNA) have been investigated in the Britton-Robinson (BR) buffer (pH = 7.2) using solubility, spectroscopic, and voltammetric methods. The measurements show that the IMC molecule, acting as an intercalator, is inserted, from the p-chlorobenzoyl part, into the cavity of the cyclodextrins as well as into the base-stacking domain of the ct-DNA double helix. Upon addition of β-CD in a buffered IMC solution, the solubility of IMC increases and the Gibbs free energies of transfer of the drug from aqueous solution to the cavity of β-CD are negative and increase negatively with increasing β-CD concentration. The interaction of IMC with CDs and ct-DNA causes hypochromism and bathochromic shifts in the absorption spectra, along with pronounced changes in the electrochemical behaviour of the drug. The stoichiometry of complexes formed in solution is inferred to be 1:1. The binding constants were calculated from the increase of the solubility, the strong hypochromism, and the decrease in peak current of IMC upon the addition of the host molecules. IMC has a higher affinity for β-CD than for α-CD, as the IMC–β-CD interaction is the most exergonic. Binding is interpreted in terms of the intercalative (hydrophobic) interactions with the ct-DNA helix (i.e., the stacked base pairs) or within CD cavity.Key words: cyclodextrin, ct-DNA, anti-inflammatory drug, indomethacin, binding constant, solubility, spectra, voltammetry.

Low or no antibody responses to human immunodeficiency virus type 1 Nef in infected carriers with subtype E, in contrast to subtype B that showed antibodies preferentially recognizing subtype-specific Nef epitopes

The viral accessory gene product Nef has been shown to play an important role in human immunodeficiency virus type 1 (HIV-1)-induced pathogenesis. Only little information is available regarding the differences in the host immune responses against Nef protein and its function in vivo among different subtypes of HIV-1. In the present study, we showed marked differences in the immune responses to Nef protein between subtypes B and E. The amino acid sequence in subtype E Nef showed 72% homology with that in subtype B. Most murine monoclonal antibodies obtained by immunization with subtype B or E Nef protein showed cross-reactivity with both Nef proteins (80 and 67%, respectively). Next, we focused on the immune responses among infected Japanese and Thai individuals. Subtyping of the individuals into B and E was carried out by enzyme-linked immunosorbent assay (ELISA) using synthetic peptides corresponding to the V3 loop representing the principal neutralizing domain. Most of the sera from these individuals reacted strongly with Gag p24 proteins derived from subtypes B and E at similar levels. However, the immune responses among these individuals to Nef protein were markedly different. Some subtype B-infected Japanese and Thai individuals (40 and 35%, respectively) showed higher levels of anti-Nef antibodies, although these antibodies preferentially recognized epitopes specific to subtype B. On the other hand, most of the subtype E-infected Japanese and Thai individuals showed low or no antibody responses to Nef proteins. Thus, immune responses to Nef were markedly different between subtypes B- and E-infected carriers, suggesting different function(s) for Nef in AIDS pathogenesis. Further, vaccine design must take into account the different subtypes of HIV-1.

Enzyme-catalyzed removal of phenol from refinery wastewater: feasibility studies

Phenols are present in petroleum refining wastewater. An enzymatic method for removing phenols from industrial aqueous effluent has been developed in the past several years. In this method, a peroxidase enzyme catalyzes the oxidation of phenol by hydrogen peroxide generation of phenoxyl radicals. These radicals diffuse from the active center of the enzyme into solution and react nonenzymatically to eventually form higher oligomers and polymers, which can be removed from wastewater by conventional coagulation and sedimentation or filtration. In this study, Arthromyces ramosus peroxidase (ARP) was applied to treat a petroleum refining wastewater containing 2 mM (188 mg/L) phenol in a batch and continuous-flow system. The latter consisted of a plug-flow reactor (PFR) where the reaction took place between phenol and hydrogen peroxide catalyzed by the enzyme in the presence of polyethylene glycol (PEG). A flocculation tank followed the PFR where alum and sodium hydroxide were added and then the polymers formed were settled in a sedimentation tank and removed from the system. Most (95 to 99%) of the phenol was removed by the same dose of ARP required for the treatment of synthetic wastewater containing an equal amount of phenol. Polyethylene glycol, as an additive, reduced enzyme inactivation and consequently reduced the enzyme dose and the cost of the treatment process. Step feeding of hydrogen peroxide was not effective in reducing the enzyme requirement. A significant removal of chemical oxygen demand was achieved when using PEG to reduce the enzyme dose.

Determination of nickel in biological samples spectrophotometrically involving complexation reaction with some thiazolylazo compounds

Three new heterocyclic azo compounds, 5(2-benzothiazolylazo)2,2 biphenyldiol (I), 5-(2-benzothiazolylazo)-8-hydroxyquinolene (II) and 4-(2-benzothiazo-lylazo)3-hydroxy-2-naphthoic acid (III) were synthesized. The formation constant of the reagents in 30% (v/v) ethanol and reactions with various metal ions were studied. These reagents (I-III) reacts with nickel ion to form (2:1) colored complex with an absorption band at 604, 635 and 643 nm. The apparent stability constants and the optimum conditions for complete color development were investigated. Beer's law is obeyed over the concentration ranges of 0.05-3.50, 0.05-4.00 and 0.05-3.10 micrograms ml-1. For more accurate analyses, Ringbom optimum concentration ranges were found to be 0.20-3.25, 0.20-3.80 and 0.20-2.90 micrograms ml-1 using reagents I, II and III, respectively. The apparent molar absorptivity and Sandell sensitivity were also calculated. The interference of various foreign ions on the determination of nickel was investigated. The proposed method has been successfully applied to the determination of nickel substrates in various biological samples.

Phase-selective a.c. adsorptive stripping voltammetry of lumazine on a hanging mercury drop electrode

The electrochemical behavior of lumazine (LMZ), an important antibacterial agent, has been studied at the hanging mercury drop electrode (HMDE). The nature of the process taking place at the HMDE was clarified. Its adsorption behavior at HMDE has been studied by using a.c and cyclic voltammetry (CV). Both the molecule and its reduced product appeared to be adsorbed at the surface of the electrode. Controlled adsorptive accumulation of LMZ on the HMDE provides the basis for the direct stripping measurement of that compound in the subnanomolar concentration level. Experimental and instrumental parameters for the quantitative determination were optimized. Phase-selective a.c voltammetry provided the best signal and gave a detection limit of 0.15 microg L(-1) (9.0 x 10(-10) mol/L) LMZ in aqueous solution. Molecules or ions which may interfere were studied.

Detection of Francisella tularensis in infected mammals and vectors using a probe-based polymerase chain reaction

We investigated the use of a TaqMan 5' nuclease assay (5NA) directed against the Francisella tularensis outer membrane protein (Fop) gene and a polymerase chain reaction-enzyme immunoassay (PCR-EIA) directed against the tul 4 gene for detection of this organism in experimentally infected mice and in field-collected tick vectors. We also evaluated the use of specially formulated filter paper (FTA) for rapid sample preparation. The 5NA had a detection limit of 1 pg of genomic DNA (<100 colony-forming units) and could be completed within several hours. The PCR-EIA could detect 1 pg of genomic DNA and 10 attograms (ag) (22 copies) of cloned insert, but takes longer to perform. Both assays were genus-specific, and successfully detected F. tularensis in mouse tissues (5NA) and in tick extracts (PCR-EIA). The FTA paper provided inexpensive, rapid, template preparation for the tick extracts, mouse tissues, and DNA obtained from clinical specimens. These probe-based assays have the potential to provide rapid, real-time/high-throughput molecular diagnostics in field situations.

5' nuclease PCR assay to detect Yersinia pestis

The 5' nuclease PCR assay uses a fluorescently labeled oligonucleotide probe (TaqMan) to rapidly detect and quantitate DNA templates in clinical samples. We developed a 5' nuclease PCR assay targeting the plasminogen activator gene (pla) of Yersinia pestis. The assay is species specific, with a detection threshold of 2.1 x 10(5) copies of the pla target or 1.6 pg of total cell DNA. The assay detected Y. pestis in experimentally infected Xenopsylla cheopis fleas and in experimentally infected monkey blood and oropharyngeal swabs. The TaqMan assay is simple to perform and rapid and shows promise as a future field-adaptable technique.

Real-time microchip PCR for detecting single-base differences in viral and human DNA

This report describes real-time 5' nuclease PCR assays to rapidly distinguish single-base polymorphism using a battery-powered miniature analytical thermal cycling instrument (MATCI). Orthopoxviruses and the human complement component C6 gene served as targets to demonstrate the feasibility of using the MATCI for diagnosis of infectious diseases and genetic disorders. In the Orthopoxvirus assay, consensus Orthopoxvirus PCR primers were designed to amplify 266-281 base-pair (bp) segments of the hemagglutinin (HA) gene in camelpox, cowpox, monkeypox, and vaccinia viruses. A vaccinia virus-specific fluorogenic (TaqMan) probe was designed to detect a single-base (A/G) substitution within the HA gene. In the C6 gene assay, a 73-bp segment of the C6 gene was PCR-amplified from human genomic DNA, and TaqMan probes were used to detect a single-base (A/C) polymorphism in the second position of codon 98. The MATCI correctly identified the nucleotide differences in both viral DNA and human genomic DNA. In addition, using a rapid DNA preparation method, it was possible to achieve sample, preparation of human genomic DNA, DNA amplification, and real-time detection in less than 1 h.

A colorimetric PCR-enzyme immunoassay to identify hantaviruses

BACKGROUND

Hantaviruses cause two serious human diseases: hantavirus pulmonary syndrome and hemorrhagic fever with renal syndrome. At least nine hantaviruses are known to be pathogenic for humans and numerous others, with unknown disease potential, have been detected in rodents. Assays to quickly identify specific hantaviruses would be useful both for clinical diagnosis and in risk assessment studies.

OBJECTIVES

The goal of our study was to develop and test a specific and sensitive PCR-based assay for identification and differentiation of hantaviruses.

STUDY DESIGN

We developed an assay that combined RNA-PCR amplification and colorimetric enzymatic detection to identify representative European, Asian, and north American hantaviruses. RNAs from 18 hantavirus strains of nine species were amplified in the presence of digoxigenin-dUTP by using a single pair of oligonucleotide primers and polymerase chain reaction (PCR) performed by using rTth DNA polymerase. Digoxigenin-labeled PCR products were hybridized in solution to virus type-specific biotinilated probes, captured onto streptavidin-coated microtiter plates and detected by horseradish peroxidase-labeled anti-digoxigenin antibodies and a chromogenic substrate.

RESULTS AND CONCLUSIONS

The assay correctly identified each homologous virus type tested. The detection limit of the assay was approximately 15 PFU or at least 50 copies of the viral genome. The assay is simple and strain-specific and is adaptable for automation, making it more practical than other available techniques for accurate and reliable diagnosis and typing of hantaviruses.

The potential of 5' nuclease PCR for detecting a single-base polymorphism in Orthopoxvirus

A fluorogenic 5' nuclease PCR assay was evaluated for its ability to specifically detect and differentiate DNA of two Orthopoxvirus species. A pair of consensus primers that target a DNA segment of the Orthopoxvirus haemagglutinin gene, and two oligonucleotide probes; each labelled with a different fluorescent reporter dye and the same quencher dye, were used in a single-tube assay. The assay is based on the 5'-->3' nuclease activity of AmpliTaq DNA polymerase that cleaves a fluorescein-labelled hybridized probe. Probe cleavage generates specific fluorescent signals whose intensity can be quantified by fluorometry. After evaluating the effects of various annealing temperatures and probe concentrations and normalizing the emission intensities of the reporter dyes, it was possible to detect and differentiate monkeypox and vaccinia virus DNAs on the basis of a single-base polymorphism. The sensitivity of the 5' nuclease PCR assay is comparable to the sensitivity of ethidium bromide-stained gels, but the assay provides higher specificity and virtually eliminates the need for laborious post-PCR processing.

Detection of Rift Valley fever virus in mosquitoes by RT-PCR

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay to detect Rift Valley fever (RVF) virus RNA in experimentally infected mosquitoes was developed. The specificity of the assay was evaluated with three other phleboviruses; sandfly fever Sicilian (Sabin), sandfly fever Naples (Sabin) and Punta Toro (MSP 3) viruses. The relative sensitivity of the assay, determined by using RVF virus RNA extracted from serial dilutions of virus culture, was approximately 50 plaque forming units. This sensitivity level was 100-fold higher when a nested PCR procedure was used. When the RT-PCR assay was used with coded samples of intrathoracically-infected and uninfected mosquito, the assay detected the virus in all infected mosquitoes. With this assay, it was possible to detect RVF virus RNA in a single infected mosquito in the background of 10, 25 or 50 uninfected mosquitoes.

Muscle actin gene from Aedes aegypti (Diptera:Culicidae)

A recombinant phagemid containing a 1,240-bp insert encoding an actin was isolated from a yellow fever mosquito, Aedes aegypti (L.), complementary DNA library. This insert (pBS-Act35) contained an open reading frame of 822 bp whose deduced amino acid sequence exhibited > 95% homology with the carboxyl terminal 274 amino acids of Drosophila melanogaster Meigen and silkworm, Bombyx mori (L.), actin genes. Reverse transcriptase-polymerase chain reaction was used to clone and determine the sequence of the additional 306 nucleotides that comprise the 5' end of the gene. The coding nucleotide sequence of the whole gene (designated Aeact-1) exhibited between 81 and 89% homology with coding sequences of D. melanogaster and B. mori actin genes, and its deduced amino acid sequence exhibited > 95% homology with those genes. The highest similarity of Aeact-1 gene at the amino acid sequence level was with B. mori and D. melanogaster muscle actins. Southern blot analysis indicated that the Aedes genome contains at least 5 actin-related sequences.

Aflatoxin B1 in common Egyptian foods

Samples of common Egyptian foods (17 nuts and seeds, 10 spices, 31 herbs and medicinal plants, 12 dried vegetables, and 28 cereal grains) were collected from markets in Cairo and Giza. A portion of each sample was extracted with chloroform, and the concentrated extract was cleaned by passing through a silica gel column. Aflatoxin B1 was determined by reversed-phase liquid chromatography with UV detection. The highest prevalence of aflatoxin B1 was in nuts and seeds (82%), followed by spices (40%), herbs and medicinal plants (29%), dried vegetables (25%), and cereal grains (21%). The highest mean concentration of aflatoxin B1 was in herb and medicinal plants (49 ppb), followed by cereals (36 ppb), spices (25 ppb), nuts and seeds (24 ppb), and dried vegetables (20 ppb). Among nuts and seeds, the prevalence of aflatoxin B1 was highest (100%) in watermelon seeds, inshell peanuts, and unshelled peanuts. The lowest prevalence and concentrations were in hommos (garbanzo beans). The highest concentrations of aflatoxin B1 were detected in foods that had no potential for field contamination but required drying during processing and storage, such as pomegranate peel, watermelon seeds, and molokhia.

Venezuelan equine encephalitis in BALB/c mice: kinetic analysis of central nervous system infection following aerosol or subcutaneous inoculation

OBJECTIVE

To investigate the routes of entry of Venezuelan equine encephalitis (VEE) virus into the brain, we infected BALB/c mice with a virulent strain (V3000) by aerosol or subcutaneous inoculation.

METHODS

Immunohistochemistry and in situ hybridization methods were used to detect VEE virus in tissues taken at daily intervals postinfection.

RESULTS

In both groups, virus in the brain first appeared in olfactory regions. Aerosol exposure caused early massive infection of olfactory epithelium, which developed into bilaterally symmetrical infection of the olfactory nerves, olfactory bulbs, and lateral olfactory tracts by day 2 postinfection. After subcutaneous inoculation, VEE in the brain also appeared first in olfactory regions, but was not detected until day 3 postinfection. By day 4 postinfection, VEE viral infection had spread throughout the brain in both groups. Vascular endothelium and the choroid plexus remained uninfected during the entire study.

CONCLUSIONS

Our findings suggest that VEE virus, whether given by aerosol or subcutaneously, first enters the brain through the olfactory tract.

An immunological factor that affects Anopheles gambiae survival

High titers of antibodies against Anopheles gambiae midguts were produced in New Zealand rabbits to identify midgut targets for an antimosquito vaccine. The serum from one of 8 rabbits (designated R2B6) killed 71.6% (Abbott's adjusted % mortality) of An. gambiae within 7 days. Mosquitoes ingesting R2B6 serum were unable to absorb their blood meal nutrients, resulting in reduced oviposition and egg hatching rates. Anopheles stephensi and Anopheles arabiensis were also killed when ingesting R2B6 serum but Anopheles freeborni, Anopheles albimanus, and Aedes aegypti were not affected. The mosquitocidal factor was a relatively large molecule (> 100,000 MW) maintained at threshold levels in the sera and killing was complement independent. Mortality, however, was not IgG mediated, as determined by protein A-sepharose fractionation. This surprising finding confounds possibilities of using antibodies against whole mosquito midguts as a step in the development of antimosquito vaccines.

Delta virus versus HBsAg in chronic active hepatitis and their relation to clinical, laboratory, and morbidity findings in bilharzial and non-bilharzial patients

This work was done to study the effect of delta virus and HBV infection, as two aetiological factors on clinical presentation, biochemical liver functions and prognosis of chronic active hepatitis (CAH) in schistosomiasis infected and non-infected patients. 66.7% of the patients were carriers for HBsAg, among them 41.7% were infected with delta virus. It was evident that the clinical presentation of the patients with positive serological markers of HBV and HDV demonstrated advancing liver disease than in the other studied groups. Moreover, the biochemical liver profile was significantly affected when the triad of chronic HBV, delta virus and schistosomiasis infection was present. This could be related to the immunosuppression caused by schistosomal infection. Furthermore, mortality rate was significantly higher in schistosomiasis infected individuals.

Anti-Onchocerca volvulus immunoglobulin subclass response in children from Sierra Leone

The humoral immune responses of a paediatric population of 224 children, 2-15 years of age, residing in an onchocerciasis endemic area of Sierra Leone, were studied to gain information that may be useful in the serodiagnosis of prepatent and low-level infections with Onchocerca volvulus. The antigen-specific levels of IgG and IgG4 were determined and evaluated in the context of the parasitological status of the child. Over 87% of the microfilaria-negative children had significant levels of antigen-specific antibodies against O. volvulus, suggesting that a large percentage of this paediatric population were harbouring prepatent or low-level infections. Over 60% of the children in the group that had detectable numbers of microfilariae in skin snips had elevated levels of O. volvulus-specific IgG4. In contrast, only 23% of the microfilaria-negative children had detectable IgG4 responses. The results presented here indicate that measures of O. volvulus-specific IgG4 may be a useful indicator of the parasitological status of children during the very early stages of onchocerciasis.

Surface-associated antigens of Brugia malayi L2 and L3 parasites during vector-stage development

Surface and metabolic labeling procedures were used to characterize the composition and the time of expression of Brugia malayi L2 and L3 surface-associated molecules as the larvae develop within the mosquito vector. Larvae were harvested from mosquito tissues at 5 (early L2), 8 (late L2) and 11 (L3) days post-infection and labeled with 125I-Iodo-Gen. The results of one-dimensional analysis showed that there is a progressive increase in the complexity of peptides associated with the surface of developing larvae, culminating in the expression of 7 major labeled components on L3s. Both L2 and L3 parasites have surface-associated components of 42, 35, 33, 19 and 17 kDa. Between days 8 and 11 of development in the insect vector, Brugia malayi undergoes the L2 to L3 molt and acquires additional major immunogenic peptides of 40 and 22 kDa. Two-dimensional analyses of extracts from 125I-labeled L2s and L3s revealed that the major 35-, 33-, 19- and 17-kDa molecules are part of a peptide complex that forms a 'ladder' between 17 and 150 kDa. To gain information on the times during which the major surface-associated molecules are produced by the parasite, larvae were labeled with [35S]methionine either in situ as they developed within the mosquito or during culture after exiting the vector. For in situ labeling, [35S]methionine was introduced into the hemolymph of infected mosquitoes by micro-injection at days 2, 5 and 8 post-infection and the larvae were allowed to develop for an additional 3 days. The results of 1- and 2-dimensional analyses of [35S]methionine-labeled extracts from vector-stage or post-vector-stage larvae indicate that the molecules associated with the surface of B. malayi L3s are synthesized between day 5 and day 11 of development in the insect host. Immediately after the larvae exit the vector, the synthesis of the 40 and 22-kDa peptides is drastically reduced or terminated.

Antigen shedding from the surface of the infective stage larvae of Dirofilaria immitis

A qualitative and quantitative analysis was made of the release of surface-associated molecules from developing Dirofilaria immitis infective-stage larvae (L3). D. immitis L3s were labelled with 125I using an Iodogen catalysed reaction and either maintained in culture or placed in chambers that were implanted into Lewis rats. The larvae released 10-20% of the labelled material each day during the first 4 days of in vitro and in vivo development. The loss of surface-labelled peptides from developing larvae corresponded with an increase in the amount of trichloroacetic acid-precipitable radioactivity found in the culture medium. SDS-PAGE analysis of the labelled material showed that the same 35 and 6 kDa components found in larval extracts were shed into culture medium by the developing parasites. Metabolic labelling studies and experiments in which larvae were labelled after different times in culture indicated that, once released, the surface-associated molecules were not replaced, and that this net loss of surface peptides resulted in a reduction in the antigenic potential of the cuticular surface. Antibodies from both immunized rabbits and naturally infected dogs immunoprecipitated the 35 kDa component. In contrast, the 6 kDa molecule was not recognized by the antibodies in any of the sera tested. Shedding of surface peptides and reducing surface antigenicity may represent mechanisms by which D. immitis infective-stage larvae evade immune attack.

Dirofilaria immitis: studies on anti-microfilarial immunity in Lewis rats

The effect of vaccination on rates of microfilarial clearance using Dirofilaria immitis in male Lewis rats was examined. Animals were immunized with whole, dead microfilariae or a PBS extract of microfilariae in Freund's adjuvant. The immunized animals, as well as untreated and adjuvant controls, were challenged intravenously with 4 x 10(5) viable microfilariae (mf). The duration of microfilaremia was 15.5 days in rats vaccinated with whole mf, 17.7 days in those vaccinated with a PBS extract, 36.3 days for those vaccinated with adjuvant alone, and greater than 70 days for the untreated group. Analysis of the anti-microfilarial IgG response by ELISA and Western blots demonstrated that immunization induced significant amounts of antibody against high molecular weight peptides, particularly a peptide located at 105 kDa. Antibody levels in both groups of immunized animals continued to rise following challenge, reaching peak levels of 78-80 micrograms/ml on the day of microfilarial clearance. Decreasing microfilaremia following challenge was associated with an enhanced recognition of low molecular weight peptides.

Dirofilaria immitis: biochemical and immunological characterization of the surface antigens from adult parasites

The molecules associated with the surface of adult Dirofilaria immitis were identified and characterized employing IODO-GEN-mediated surface labeling methods. D. immitis female and male parasites were found to have a limited number of surface-associated proteins (17.5, 16, and 14.5 kDa) and glycoproteins (49 and 20 kDa) which were readily extracted from parasite homogenates in the absence of detergent. The major surface labeled proteins and glycoproteins were antigenic in rabbits, but appeared to elicit only a weak humoral response in dogs with patent dirofilariasis. In addition, a 10- to 6-kDa surface-associated glycolipid was identified which may form a coat on the outside of the parasite and play a role in immune evasion. In immunoprecipitation experiments, the glycolipid was not recognized by the antibodies from rabbits exposed to the glycolipid or by antibodies in the sera of patently infected animals. The glycolipid and the 14.5-kDa surface protein were selectively released by the adult parasite during in vitro culture.

Antibiotics and immunity: effects of antibiotics on mitogen responsiveness of lymphocytes and interleukin-2 production

The immunomodulating properties of antimicrobial drugs may have important implications in prescriptive practice. This is particularly so for patients whose immune system has been compromised. In this study, tetracycline, cephalothin, rifampicin, polymyxin B and nitrofurantoin reduced mitogen responsiveness of both B and T lymphocytes of mouse spleen cells and human peripheral blood lymphocytes in vitro in a dose-dependent fashion. Ampicillin, chloramphenicol, gentamicin, streptomycin and erythromycin had no effect. In the in vivo study none of the antibiotics affected mouse spleen cell transformation in response to mitogen. The addition of interleukin-2 (IL-2) did not prevent the effect of the antibiotics tested on human lymphocytes in vitro. Cephalothin, chloramphenicol and gentamicin decreased IL-2 production by mouse spleen cells in vitro.

Antibiotics and immunity: effects of antibiotics on natural killer, antibody dependent cell-mediated cytotoxicity and antibody production

We studied the effects of antibiotics on natural killer (NK), antibody dependent cell-mediated cytotoxicity (ADCC) and immunoglobulin production. When human peripheral blood lymphocytes were incubated overnight with the antibiotic before the assay, nitrofurantoin significantly reduced NK but not ADCC activity. Nitrofurantoin also suppressed both spontaneous and interferon-enhanced NK activities in a dose-dependent fashion. Though it did not affect spontaneous ADCC activity, nitrofurantoin suppressed interferon enhancement of ADCC. Chloramphenicol significantly decreased the number of plaque forming cells in mice. In addition to chloramphenicol, tetracycline, rifampicin, cephalothin, polymyxin B and nitrofurantoin reduced mitogen-induced polycloned immunoglobulin synthesis. Results of this study may have clinical relevance, especially in treating immunocompromised patients.